The DNA sequences of two promoters for the phage-specific T7 RNA polymerase have been determined. The small restriction fragments, approximately 100 basepairs, carrying these promoters are self-contained in vitro transcription units, the RNA polymerase initiating and elongating small mRNAs. The precise molecular interactions of the polymerase with these promoters will be examined by spectroscopic, chemical modification, radiolabeling and kinetic methods. The molecular properties of T7 RNA polymerase are being determined as well as the sequence of the polymerase gene and hence the amino acid sequence. Multinuclear NMR (1H, 31p and 19F) methods are being used to probe the structure of the complexes of gene 5 protein of bacteriophage fd and gene 32 protein of bacteriophage T4 with oligodeoxynucleotides of defined sequence. The role of phosphorylation-dephosphorylation in the structure and function of non-histone chromosomal proteins is under investigation.